Preparation

Combine first 3 ingredients in small saucepan. Bring to boil. Reduce heat; cover and simmer until prunes are soft and juice is reduced to 2 tablespoons, about 6 minutes. Transfer prunes to bowl; reserve juice. Chill prunes until cold, about 2 hours. Cut into quarters.

Cut peel and white pith from oranges. Working over bowl to catch juice and using small sharp knife, cut between membranes to release segments. Combine 2 tablespoons orange juice from bowl, oil, vinegar, grated orange peel, and reserved prune juice; whisk to blend. Season dressing with salt and pepper.